Drill steel centralizer



1955 D. F. SAMHAMMER DRILL STEEL CENTRALIZER 2 Sheets-Sheet 1 Filed July 7, 1954 Dec. 20, 1955 ER' 2,727,725

DRILL STEEL CENTRALIZER Filed July 7, 1954 2 sheets-Sheet 2 INVENTOR flow/440 FJFIM/MMMER ATTORNEY United States Pa t p H DRILL STEELCENTRALIZER Donald F. Samhammer, Utic'a, N. Y., assignor to Chicago Pneumatic Tool Company, New York, N; Y., a corporation of New Jersey Application July 7, 1954, Serial No. 441,728 1 t 12 Claims. ci. 255-51 This invention relates to rock drills andmore particularly improvements a centralizer, or guide, for a drill steel as used in a rock drill of the'd'rifter 'type.

In rock drilling operations utilizing'drills of the drifter type, guide means are often provided to prevent the'drill steel from crawling when starting a hole on irregular work surface. Such guide means are of various types, including arrangements wherein a pair of pivoted'arms is adapted to guidingly grasp the drill steel, and arrangements wherein a guide arm isadapted to swing in anarc parallel to the movement of the drill steel, and which includes a drill steel lock in the form of a latch element. The device of the present invention is of the latter type and distinguishes over known devices of the prior 'art by providing for automatic operation of the latch element by direct engagement with the drill steelduring movement of the guide arm, which results in an arra'ngementof extreme simplicity and one which assures positive locking action. The device of the invention also includes a power operated guide arm actuator, which provides for remote control of the guide arm if desired.

An object of the invention is to provide a drill steel centralizer which will prevent a drillsteel from crawling when starting a hole in an irregular work surface.

A further object of the invention is to provide a drill steel centralizer with an improved latchelement arrangement which is operated by directengagement with the drill steel, to either lock or unlock the drill steel from guided condition. e

Further objects are to provide a drillsteel centralizer which is extremely simple in'structure, of rugged construction, efficient and reliable in operation, and which may be remotely controlled.

These and further objects and features of the invention will become more'apparent from the following description taken in consideration-with the accompanying drawings in which: i Fig. l is a side elevational view, partly in section and broken away in part, of a drill steel centralizer embodying the invention; a

Fig. 2 is an end view of the drill steel centralizer of Pi 1; v iig. 3 is a top view of a portion of the drill steel centralizer; I

Fig. 4 is an end view, partly in section, of a portion of the drill steel centralized as seen from line 44 in Fig. 3; Fig. 5 is a plan view of a latchelement used in the device of Fig. 1;

Fig. 6 is an end view in section as seen from line 6-6 in Fig. 5;

Fig. 7 is a perspective view of a latch spring used in the device of Fig. 1; and i Fig. 8 is a sectional View of a portion of the drill steel centralizer as seen from line 88 in Fig. 2. 7

Referring now to the drawings, and more particularly to Fig. 1 thereof, numeral 11 indicates the front end of a rock drill of the drifter type, which issupported for longitudinal movement upon a frame, or guide shell 12 in the manner well known to those skilled in the art. Atfixed to the forward portion of the guide shell 12, is a drill steel centralizer arrangement embodying the features of the invention, which arrangement cornprises two operative parts viz, a guide arm assembly 13,- and aguide arm actuator assembly 14. I

The ide arm assembly-13, includes a guide a 15 which has a pairof ears 17 at the lower end, ahead por-" tion 18 at the'upper end having a drillst'eel slot 19, and a" lock, or latch element 21 pivotally afli'xed-to the head portion for movement intopbsitionFabove the slot 19. The cars 17 are arranged for connection to a pin 22 which is supported for rotary movement in a: bracket 23, which is attached'to the forward end of the guide shell 12 in a manner as to maintain'the axis 'of pin 22 at right anglesto the path of movement of the rock drill, The drill steel slot 19 is positioned so as to receive a drill steel 24 of. the rock drill when the guide arm is invertical'po'sition, whereby the drill steel will be held inguided condition. The latch element-21 is'positioned at an angle of approximately 15 relative a plane perpendicular to the axisof the guide arm as best seen in Fig. 2.. A bolt 26-having a nut 27,

is arranged to pivotally secure-the latch element in posi-' tion upon the guide arm. The end of latch element-21 to provide better camming action to the latch elementwhen it engages the drill steel-24, so asto rotate the latch 'element out-of locking positionythechamfer 31is effective when the drill'arm is being raised to vertieal'or-operative position, while thechamfer 32 is effective when the drill arm is being lowered to horizontal; or non-operative position. v

- A spring 33 surrounding the bolt 26', is located-beneath the latch element, and has arms, or ends 34 and'36'whieh are formed to engage the latch. element on each side. Vertical slots 37 and 38 are formed in the latch elemeut'to receive the ends 34 and 36*respectively of the spring 33, the extremities of said spring enteringa hole 40 formed in the latch element. The width of slots 37 and 38 as well as the diameter of hole 40 is greater than that of the spring ends so that one of said spring ends cancock in the respective slot and holewhen the latchis rotated, thereby preventing undue distortion on. the spring arm under action. The'spring ends 34 and '36 are arrangedoneach springresistance to the latch element ineitherdirection of rotation. A pin 41 is afiixed in the guide arm to project intoa groove formed on" bolt 26,'to prevent the latter from rotating. Formed integral-with the head portion 18 are drill steel guidemeans' in the form of two fingers 43 which are flared in a rearward direction, said fingers being effective to guide the drill steel '24 into'the' drillsteel' slot verticahorlhold- 19 when the guide arm is being swung to ing position. K

The guidearm 16 has a' bore 44 for recep tion of a guide arm positioning means including aspring'46 compressively engaging a wedge type plunger 47, which isia dap'te d to enter one of two slots 48, 49 formed in theb ra'cket 23. The purpose of the gui de arm positioning-means is to maintain the guide arm in either vertical or horizontal position, as willbe easily understood. The plunger 47 has a flat portion 51 on the side thereof, for, engagement by. a pin 52 aflixed in the guide, arm 16, wherebythe plunger 47 is maintained in guided condition forproper engagement with slots 48, 49. U

The operation of the above Ia m n b lie e t anitetappa nt, a d b ie y et e e ee- 9.1 .55.

described as follows: Assume that the guide arm assembly 13 is iii horizontal, or non-operative position, and the drill steel 24 is in position in the drill 11, and drilling operation is about to commence, the tool operator need merely swing the guide arm assembly into vertical position, whereupon the latch element 21 will be automatically swung into drill steel holding position as shown in Figs. 1 and 2. In arriving at such position, the latch element will be forced from over the drill steel slot 19, by virtue of sliding engagement with the drill steelin the region of the chamfer 3-1.. As soonas the drill steel is in position in slot 19, andthe latch element is clear of the drill steel, the latch element will be swung into holding position by action of the spring 33. The drill steel 24 is thus held in guided position so that it will not crawl during start of a hole an irregular work surface.

As the drill 11 approaches the end of travel upon the guide shell 12, it engages the fingers 43 of the guide arm 16, thus rotating the latter forwardly toward horizontal position. During such movement the latch element 21 will be forced from over the drill steel slot 19, by virtue of .sliding engagement with the drill steel in the region of the chamfer 32. As soon as the latch element is forced out of contact with the drill steel, the latch element will be swung back into position over the now empty drill steel slot 19, by action of the spring 33.

The guide arm actuator assembly 14, which is adapted to provide power operation of the guide arm assembly 13 by remote control, includes a cylinder 53, front and rear end cylinder heads 54, 56 respectively, and a piston 57 having a piston rod 58 extending through and supported by the front end cylinder head 54. Two bolts 59 extend through flanges formed on cylinder heads 54 and 56 to maintain the latter in position on the cylinder 53. The front cylinder head 54, has a passageway 61 opening unto the inside face, which passageway extends into a bore 62 threaded to receive a pipe fitting 65. The rear cylinder head 56 has a centrally disposed hole 63 which is threaded to receive a pipe fitting 70. It will be seen that application of pressurized fluid via passageway 61 will force the piston 57 rearwardly in the cylinder, assuming of course that the hole 63 is open to exhaust, and that application of pressurized fluid via hole 63 will force the piston 57 forwardly in the cylinder, assuming that passageway 61 is open to exhaust.

The front cylinder head 54 has a horizontally disposed flange 64v (Fig. 2) which is-afiixed to the underside of guide shell 12, by bolt means 66, and which supports the actuator assembly 14 in operative position.

The external end of the piston rod 58 has a pin 67 affixed thereto, which pin projects from each side of the piston rod to slidingly engage slots 68 formed in a pair of crank arms 69 which extend from a hub portion 71 afiixed to the pin 22. In such manner the reciprocal movement of piston 57 is arranged to provide rotary motion of the guide arm assembly 13, so that the latter may be raised or lowered in accordance with requirements. It is pointed out that the guide arm assembly 13 may be used manually, and with or without association with an actuator assembly of the type described.

What is claimed is:

1. In a rock drill mounted for movement in a drill shell, a drill steel centralizer having a guide arm which is pivotally affixed to the front end of the drill shell and is adapted to swing in a plane coincident with the path of movement of the drill, said guide arm having a head portion including a drill steel slot which in one position of the guide arm is adapted to supportingly engage a drill steel operatively positioned in the rock drill, a latch element rotatably mounted upon the head portion and arranged to extend over the drill steel slot and movable by sliding engagement with the drill steel, and resilient means adapted to urge the latch element into position over the drill steel slot.

'2. In a rock drill mounted for movement in a drill shell,

a drill steel centralizer having a guide arm which is pivotally afiixed to the front end of the drill shell and is adapted to swing in a plane coincident with the path of movement of the drill, said guide arm having a head portion including a drill steel slot which in one position of the guide arm is adapted to supportingly engage a drill steel operatively positioned in the rock drill, a latch element rotatably mounted upon the head portion and arranged to extend over the drill steel slot and movable by sliding engagement with the drill steel, a spring means adapted to urge the latch element into position over the drill steel slot, and drill steel guide fingers formed on the head portion and adapted to guide the drill steel into the drill steel slot.

3. In a rock drill having a drill steel centralizer according to claim 2, wherein a lip portion is arranged on the head portion to project over the drill steel slot to engage the upper surface of the latch element when it is in position over the drill steel slot.

4. In a rock drill having a drill steel centralizer according to claim 3, wherein said latch element is disposed to rotate in a plane forming an angle of approximately 15 with respect to the axis of the guide arm.

5. In a rock drill having a drill steel centralizer according to claim 4, wherein a guide arm positioning means is arranged to maintain the guide arm in either a vertical or horizontal position, said guide arm positioning means including a plunger disposed within the guide arm which is spring biased for engagement with slots formed in a bracket atfixed to the drill guide shell.

6. In a rock drill having a drill steel centralizer according to claim 1, a guide arm actuator assembly afiixed to the drill shell and adapted to provide rotary movement of said guide arm about its pivot.

7. In a rock drill having a drill steel centralizer according to claim 6, said guide arm actuator including a cylinder, a piston slidably maintained within the cylinder, front and rear cylinder heads positionally maintained upon the cylinder, a piston rod connected to the piston and supported for sliding movement Within the front head and extending exteriorly thereof, and a crank arm arranged between the piston rod and the guide arm.

8. In a rock drill having a drill steel centralizer according to claim 7, pressure fluid connections in the front and rear cylinder heads adapted for alternative delivery of pressure fluid to opposite sides of the piston to cause reciprocable movement of the piston within the cylinder.

9. In a rock drill having a drill steel centralizer according to claim 8, wherein drill steel guide fingers are formed on the head portion and which are adapted to guide the drill steel into the drill steel slot.

10. In a rock drill having a drill steel centralizer according to claim 9, wherein a lip portion is arranged on the head portion to project over the drill steel slot to engage the upper surface of the latch element when it is in position over the drill steel slot.

11. In a rock drill having a drill steel centralizer according to claim 10, wherein said latch element is disposed to rotate in a plane forming an angle of approximately 15 with respect the axis of the guide arm.

12. In a rock drill having a drill steel centralizer according to claim 11, wherein a guide arm positioning means is arranged to maintain the guide arm in either a vertical or horizontal position, said guide arm positioning means including a plunger disposed within the guide arm which is spring biased for engagement with slots formed in a bracket affixed to the drill steel shell.

References Cited in the file of this patent UNITED STATES PATENTS 1,697,648 Hansen Jan. 1, 1929 1,789,859 Bayles Ian. 20, 1931 2,204,352 Fuehrer June 11, 1940 2,333,487 Nast Nov. 2, 1943 2,389,532 Nelson Nov. 20 1945 

